Title: 34 State of stress in the Earth's lithosphere
Abstract: Large portions of intraplate regions (lateral dimensions of 10 3 –10 4 km) are characterized by relatively uniform stress fields suggesting that the state of stress in the brittle upper crust is dominated by large-scale tectonic processes. In general, principal stresses in the crust are in vertical and horizontal planes. In intraplate areas, in situ stress measurements and inferences based on topography and flexure all suggest that shear stresses in the upper lithosphere are fairly large and seem controlled by the frictional strength of the faulted crust. Unlike the interiors of plates, plate boundary faults (like the San Andreas fault and subduction zones) appear to be quite weak and slip at low levels of shear stress. At sufficient depth below the brittle upper lithosphere, stresses are likely controlled by the ductile flow properties of the constituent rocks and minerals. Plate driving forces are sufficient in magnitude to maintain the intraplate lithosphere in a state of frictional failure. This frictional failure is manifest as slow, steady-state creep deformation in the lower crust and upper mantle and brittle deformation in the upper crust.
Publication Year: 2002
Publication Date: 2002-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 32
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